alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Generic Webshell Accessed on External Server"; flow:established,to_client; file.data; content:"<title>Genol Shell"; nocase; fast_pattern; content:"><b>Uname|20 3a 20|Linux|20|"; nocase; distance:0; classtype:web-application-attack; sid:2030073; rev:2; metadata:affected_product Web_Server_Applications, attack_target Client_Endpoint, created_at 2020_05_01, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_05_01;)